If only there was a way to do effective cardio training without running. Oh, wait, there's boxing and mixed martial arts. Fast-paced workouts can be used for boxing and MMA training in addition to just straight-up getting shredded. "This workout is a form of high-intensity interval training (HIIT) since your heart rate increases and decreases," says Oscar Hernandez, C.P.T., the designer of the routine. "Incorporate it into your weekly routine as a day of cardio to burn calories." Square up and get ripped fast.

WORKOUT INSTRUCTIONS

Use 16-ounce boxing gloves. Each round is 3 minutes. Each active rest period is 1 minute.